The present invention relates generally to apparatus for throwing or projecting objects. More particularly, the present invention relates to apparatus for serving tennis balls to a practicing player.
According to my U.S. Pat. No. 3,602,208, the disclosure of which is incorporated herein by reference, a known apparatus for throwing tennis balls, has a driving, controlling and throwing device. Therein, the apparatus for throwing tennis balls can vary the horizontal direction of the thrown balls and the speed of the thrown balls. Briefly, horizontal direction is changed by moving support 9 (FIG. 2) about a shaft 12. The cam 72 is moved by a cam follower 71. Each lobe of the cam 72, when coming into contact with the cam follower 71, causes angular displacement of support 9 and the throwing mechanism. Speed is adjusted by varying the distance between the drive pulley 16 and the pulley 14. The pulley 14 is adjustable through angular level 74 which is moved by a joint 74a (FIG. 1), link 76 (FIGS. 1 and 2), and universal joint 76a (FIG. 2) connected to cam follower lever 77 (FIG. 1) attached to cam follower 78 of cam 79. A similar arrangement is provided in the present invention for adjusting horizontal direction and speed. A mechanism for releasing the release element 30' is also disclosed and includes a cam wheel 66 (FIG. 1) with lobe 67 closing a switch 44. The switch 44 (FIGS. 6 and 8) actuates an electromagnet 41 to cause release element 38 to be moved via member 42.
However, with high exit velocities and a more rapid throwing sequence, the tennis balls have a non-uniform trajectory whereby, at the same time, the guiding of the balls into the track of the guide spiral and the closing of the closure member are subjected to interference.
Thus, it has already been proposed to overcome this dificiency so that a jerk-free expulsion of the balls is guaranteed by, on the other hand, an automatic compensation of the throwing device, especially by a compensation of the ball weight during the supply of the balls to the exit opening of the throwing device and on the other hand, by an improved control of the release and closure member.
However, with these known devices, a sufficiently strong and accurate ball delivery is only possible to a limited extent whereby a variation of all possible game procedures is limited.
According to the present invention there is provided an apparatus for throwing or hurling objects. The apparatus has a hurling device including a striker mounted on a rotatable member for movement in a circular path and pivotal into an operative position extending radially outwardly of the member for striking an object supplied to a guide track of the apparatus. The object is thereby projected from the apparatus. Selectively operable means are provided to cause the striker to pivot into the operative position. Means responsive to the rotational movement of the member are provided for pivoting the striker into a nonoperative position subsequent to the striker striking an object.
A preferred embodiment described hereinafter includes an apparatus for serving tennis balls in which each ball, located in the serving position of a supporting and guiding device, is served by a rotating striker or serving plate. Thus, practically any required ball range and height of flight path can be achieved.
A further advantage of the preferred embodiment rests in the fact that the ball located in the serving position is stationary with respect to the rotating serving device whereby a quieter running of the apparatus is facilitated.
A pivotable adjustment plate which is common to a control device, the supporting and guiding device as well as the serving device is also preferably provided. In this way, an accurate vertically and laterally adjustable serving angle (i.e., elevation and azimuth angle), adjustable with reference to the axis of rotation, is guaranteed.